Technical Field

[0001] The present invention relates broadly to a hybrid-powered multihull surface vessel and relates particularly, although not exclusively, to a hybrid-powered trimaran.

BACKGROUND

[0002] The prior art literature is replete with disclosures of multihull vessels powered by a combination of combustion and electric engines. In the patent literature, there are several hybrid trimarans including the unmanned trimaran of Chinese patent application no. 110065588A by Zhang et at. Zhang et al discloses an unmanned vessel that is designed to operate both at and below the water’s surface. The main hull of Zhang etal includes a propeller powered by a hybrid engine (combustion fuel and electricity) whereas its secondary hulls are each driven by an electric screw. When operating at surface level, the unmanned vessel of Zhang etal is driven by the main propeller and electric screws operating simultaneously. In its underwater mode of operation, the vessel is powered by electricity alone where propulsion is provided by either the main propeller and the electric screws, or the electric screws alone.

Summary of Invention

[0003] According to the present invention there is provided a hybrid-powered multihull surface vessel comprising: a main hull including first propulsion means operatively coupled to a combustion engine located at the main hull; a supplementary hull laterally spaced from and connected to the main hull to increase the surface stability of the main hull, the supplementary hull including second propulsion means operatively coupled to an electric motor located at the supplementary hull, the second propulsion means being driven via the electric motor independent of the combustion engine which drives the first propulsion means; an onboard control system arranged to control the combustion engine and the electric motor for surface sailing of the vessel in either i) a primary propulsion mode where propulsion of the vessel at the surface is effected at relatively high speed via the combustion engine and the associated first propulsion means alone, or ii) a secondary propulsion mode where propulsion of the vessel at the surface is effected at relatively low speed via the electric motor and the associated secondary propulsion means alone .

[0004] Preferably the control system operates in the primary propulsion mode to deactivate the electric motor, and in the secondary propulsion mode to deactivate the combustion engine. More preferably the control system operates in the secondary propulsion mode to deactivate an electrical generator which functions to recharge batteries used to power the electrical motor associated with the second propulsion means.

[0005] Preferably the vessel also comprises a source of electricity located at the main hull and operatively coupled to the electric motor to power it for actuation of the second propulsion means. More preferably the source of electricity from which the electric motor is powered includes one or more batteries located at the main hull of the multihull. Still more preferably said one or more batteries are rechargeable and operatively coupled to an electrical generator located at the main hull and configured for recharging said batteries. Even more preferably the electrical generator is fuelled by combustible fuel stored at the main hull of the multihull. Alternatively or additionally, the rechargeable batteries are operatively coupled to one or more solar panels mounted to either the main or the supplementary hulls and configured for recharging said batteries.

[0006] Preferably the combustion engine associated with the first propulsion means is an internal combustion engine. More preferably the internal combustion engine is a diesel engine fuelled by diesel fuel located at the main hull. Still more preferably the electrical generator for recharging the batteries associated with the electric motor and the second propulsion means includes another internal combustion engine fuelled by at least some of the diesel fuel used to fuel the diesel engine.

[0007] Preferably the multihull is in the form of a trimaran where the main hull is a centremost hull, and the supplementary hull is one of a pair of side hulls connected to and laterally spaced either side of the centremost hull. Alternatively, the multihull is in the form of a stabilised monohull where the supplementary hull is one of a pair of stabilisers connected to and laterally spaced either side of the main hull. In this variation, the pair of stabilisers are in the form of a pair of outriggers located either side of the main hull.

[0008] Preferably the second propulsion means includes a pair of second propellers dedicated to respective of the pair of side hulls of the trimaran. More preferably said pair of propellers are driven, via respective of their electric motors, in concert thereby providing effective steerage of the trimaran. Still more preferably the pair of propellers and their respective electric motors are designed for relatively low speed propulsion of the trimaran.

[0009] Alternatively or additionally, the vessel includes one or more bow thrusters mounted to the main hull to promote steerage of the vessel. In this variation, the vessel includes one or more supplementary batteries arranged to electrically power the bow thrusters, said supplementary batteries being recharged via one or more of the electrical generator, said one or more batteries associated with the electric motor, or said one or more solar panels.

[0010] Preferably the first propulsion means includes a first propeller dedicated to the main hull. More preferably the first propeller and the combustion engine are designed for relatively high speed propulsion of the vessel.

[0011 ] Preferably the vessel is an unmanned surface vessel.

Brief Description of Drawings

[0012] In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a hybrid-powered multihull surface vessel will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of an embodiment of a hybrid-powered multihull surface vessel constructed in accordance with the present invention; Figure 2 is a perspective view with decks removed from the hybrid-powered multihull surface vessel of figure 1 ;

Figure 3 is a side elevation of the hybrid-powered multihull vessel of the preceding figures;

Figure 4 is a front view of the hybrid-powered multihull vessel of the preceding figures;

Figure 5 is a plan view of the hybrid-powered multihull vessel of the preceding figures;

Figure 6 is a plan view with decks removed from the hybrid-powered multihull vessel of the preceding figures.

Detailed Description

[0013] As seen in figures 1 to 6, there is an embodiment of a hybrid-powered multihull surface vessel 10 according to the invention. The surface vessel 10 is configured as an unmanned surface vessel (USV) although it will be understood that the invention as broadly defined also extends to manned or otherwise crewed vessels. In this embodiment the multihull USV 10 broadly comprises:

1. a main hull 12 including first propulsion means 14 operatively coupled to a combustion engine 16;

2. a supplementary hull such as 18a laterally spaced from and connected to the main hull 12 to increase the stability of the main hull 12, the supplementary hull 18a including second propulsion means 20a operatively coupled to an electric motor 22a located at the supplementary hull 18a;

3. an onboard control system shown schematically in figures 2 and 6 as 40 arranged to control the combustion engine 16 and the electric motors 22a/b to effect sailing of the multihull 10 at the surface in either: i) a primary propulsion mode where propulsion of the multihull 10 is effected at a relatively high speed via the combustion engine 16 and the first propeller 32 alone; or ii) a secondary propulsion mode where propulsion of the multihull 10 is effected at relatively low speed via the electric motors 22a/b and the associated second propellers 34a/b alone.

[0014] The combustion engine 16 is in this example in a conventional manner located within the main hull 12. It will be understood that the second propulsion means 20a is driven via the associated electric motor 22a independent of and separate to the combustion engine 16 which drives the first propulsion means 14.

[0015] In this embodiment the multihull vessel 10 also comprises a source of electricity in the form of a bank of batteries 24 located at the main hull 12. The batteries 24 are operatively coupled to the electric motor such as 22a to power it for actuation of the second propulsion means 20a. The batteries 24 also provide electricity to the vessel 10 for its onboard electrical “house” loads. The batteries 24 of this embodiment are rechargeable and operatively coupled to a pair of electrical generators 26a and 26b also located at the main hull 12 and configured for recharging of the batteries 24. The electrical generators 26a/b are fuelled by combustible fuel stored at the main hull 12 of the multihull 10. In this example the combustible fuel is diesel fuel held in a storage tank 28 within the main hull 12.

[0016] The combustion engine 16 of this embodiment is an internal combustion engine operatively coupled to the first propulsion means 14 via a gearbox 30. The internal combustion engine 16 is in this example a diesel engine fuelled by diesel fuel held within the storage tank 28. The diesel engine 16 and the electrical generator 26a are thus fuelled by diesel fuel from the same storage tank 28. It will be understood that the combustion engine 16 and the electrical generators 26a/b may be fuelled from separate sources holding the same fuel, such as diesel, or different fuels depending on the requirement of the combustion engine 16 and the electrical generators 26a/b.

[0017] In this embodiment the multihull vessel 10 is in the form of a trimaran where the main hull 12 is a centremost hull, and the supplementary hull 18a is one of a pair of side hulls 18a and 18b. The side hulls 18a/b are physically connected to and laterally spaced either side of the centremost hull 12. In an alternative configuration, the multihull vessel may be in the form of a stabilised monohull (not shown) where the supplementary hull is one of a pair of stabilisers connected to and laterally spaced either side of the main hull. In this variation, the pair of stabilisers are in the form of a pair of outriggers located either side of the main hull.

[0018] In this embodiment the first propulsion means 14 includes a first propeller 32 arranged to extend beneath the main hull 12 in a conventional manner. The first propeller 32 and the combustion engine 16 are together designed for relatively high speed propulsion of the vessel 10 at the surface. The trimaran 10 of this example may under the influence of the first propeller 32 and the diesel engine 16 travel at high speeds. In this embodiment the second propulsion means 20a/b includes a pair of second propellers 34a/b dedicated to respective of the pair of side hulls 18a/b of the trimaran 10. The propellers 34a/b are driven via their respective electric motors 22a/b for relatively low speed propulsion of the trimaran 10 at the surface. It is expected that for motoring at low speeds the electric motors 22a/b will each be rated at low power. The propellers 34a/b of this example are of a conventional folding design where the blades of the propeller 34a/b collapse and feather when it is inoperative. In an alternative arrangement, the second propulsion means may include retractable or tilting legs of a conventional design. It will be understood that the pair of second propellers 34a/b being mounted to the laterally spaced side hulls 18a/b provide the capability to assist with steerage of the trimaran 10. For example, the trimaran 10 may be steered to port by powering the second propeller 34a dedicated to the sideboard side hull 18a whilst the second propeller 34b dedicated to the port side hull 18b is inactive.

[0019] The primary propulsion mode at high speed is typically required where the trimaran 10 is “delivered” to a relatively distant location and generally no functional purpose other than motoring at the water’s surface to its destination is provided by the multihull 10 in this mode of operation. In the primary propulsion mode, the control system 40 deactivates the electrical motors 22a/b which are likely to be ineffective at this high speed. The propellers 34a/b of the second propulsion means 20a/b may fold to reduce drag, or alternatively the leg associated with the propeller may retract or tilt out of the water. Furthermore, with the electric motors 22a/b inactive, the associated batteries 24 are held at substantially full charge in preparation for low speed sailing under the influence of the electric motors 22a/b and the associated second propellers 34a/b.

[0020] The secondary propulsion mode at low speed is typically required where the multihull 10 is loitering or operating in stealth at the water’s surface and generally within a localised region. In the secondary propulsion mode, the control system 40 of this embodiment is arranged to deactivate the combustion engine 16. The control system 40 operates to provide propulsion of the trimaran 10 which when:

1. loitering relies upon the electric motors 22a/b alone with the associated batteries 24 being recharged as necessary by activation of the electrical generators 26a/b; or

2. operating in stealth relies upon the electric motors 22a/b with adequate battery storage wherein the electrical generators 26a/b are deactivated.

[0021] The onboard control system 40 of this example is operatively coupled to the electric motors 22a/b via cabling 42a/b, and the combustion engine 16 via cabling 44. It will be appreciated that the control system 40 may communicate wirelessly with either or both of the electric motors 22a/b and the combustion engine 16. The control system 40 may include alternative or supplementary control paths. For example, fuel to the combustion engine 16 may be controlled by an isolation valve (not shown) located on a fuel line 46 between the storage tank 28 and the combustion engine 16.

[0022] In this embodiment the trimaran 10 includes one or more solar panels such as 48 mounted to the deck 49 of the main hull 12 and configured for recharging the batteries 24. This recharging of the batteries 24 via the solar panels 48 may be required:

1. where the trimaran 10 operates in the stealth mode and recharging of the batteries 24 is required but without activating the electrical generators 26a/b; or

2. in the event there is insufficient fuel to fuel the electrical generators such as 26a/b in recharging the batteries 24.

[0023] In this embodiment, the trimaran 10 or other multihull vessel includes an underwater appendage such as a keel 50 fitted to the main hull 12. The keel 50 is in this embodiment substantially hollow and thus internally defines a cavity (not shown). The cavity is designed to house or locate a payload such as a winch from which a cable is deployed having a remote device connected at its distal end. The cable is deployed via an opening in the keel as described in the applicant’s international patent application no. PCT/AU2017/050553. The contents of this international patent application are to be considered included herein by way of this reference.

[0024] In this embodiment, the trimaran 10 includes a rudder 52 mounted to a transom 54 of the main hull 12. The rudder 52 provides effective steerage of the trimaran 10 in a conventional manner. In an alternative arrangement (not shown) the trimaran may be steered via a rudder located at the rear of each of the side hulls.

[0025] Now that a preferred embodiment of the hybrid-powered multihull vessel has been described it will be apparent to those skilled in the art that it has the following advantages:

1. the provision of an electric motor and its associated propulsion means in the supplementary hull lends itself to independent “powering” of the trimaran where the combustion engine operates in parallel with and separate to the electric motor;

2. the hybrid-powered multihull is configured to operate in either of its high speed primary propulsion mode or relatively low speed secondary propulsion mode;

3. the relatively low power electric motors are powered by relatively heavyweight batteries located in the main hull remote from the side or supplementary hulls which can thus be relatively small and lightweight;

4. the electric motors and their associated propulsion means assist with steerage possibly eliminating the need for bow thrusters in the main hull.

[0026] Those skilled in the art will appreciate that the invention as described herein is susceptible to variations and modifications other than those specifically described. For example, in the event the multihull vessel requires bow thrusters for manoeuvrability, supplementary batteries may be provided in the main hull to electrically power the bow thrusters. The supplementary batteries would in this instance be recharged via the electrical generators or the optional solar panels when included in the design. The diesel engine of the preferred embodiments may be replaced with any other combustion engine and the combustion fuel selected depending on the engine requirements. The multihull vessel may include more than one fuel storage tank where for example one tank is dedicated to the combustion engine with another tank dedicated to the electrical generators. The combustion engine may be one of a pair of side by side engines each having their respective propulsion means in the form of twin screws.

[0027] All such variations and modification are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.